The development of Internet sales and the shipping of packages and goods in response to Internet orders has elevated the importance of operations in warehouses of those who provide the goods. Typically, goods are stored in warehouses and orders are received from buyers, whether through the Internet or other, more conventional means, such as from mail-order or telephone order intake. The goods are then selected in accordance with the customer's order, and are shipped via delivery or mail service.
It is important to operate distribution centers, their associated warehouses, and the processes for picking or sorting of the ordered goods in an efficient manner. This insures that a high volume of orders can be processed through the warehouse and that operation costs can be kept to a minimum. Product picking for consumer orders is different from order processing for an industrial customer. The number of items picked for consumer orders tends to be rather small, possibly as low as one or two items per order, compared to tens or hundreds of items picked for industrial customers. The number of orders processed per hour to maintain the same return on investment is far greater for consumer sales than for industrial sales. Thus, it is important to have systems and procedures in place to process each order very quickly.
These systems should take into account the need for returning items to stock. Returns take two forms, depending on whether the item is un-opened. Un-opened items are generally returned to stock and are handled as a reverse pick (or put), in which the picking specialist simply returns the item to the proper storage location. Opened items, for return to the manufacturer, are generally handled in a separate area, with locations associated with each manufacturer, rather than for each particular product.
U.S. Pat. No. 5,781,443 discloses an inventory and picking system for a plurality of bins or storage locations on shelves. The shelves each have an electronic module for displaying information about three separate items on the shelves. The modules also have three infrared light emitting diodes and three infrared detecting circuits for detecting light that is reflected, such as light reflected from a hand that reaches into the bin or storage area. This system is subject to error from dust or other anomalies in the atmosphere or generally in a dusty warehouse, which may give off falsely positive feedback to the controller.
One way to manage orders in a manual system is disclosed in U.S. Pat. No. 5,812,986 to Danelski. This patent discloses a picking system in which an order is received and sent to a picking system computer. The system includes an RF module on each storage site or bin in the storage system. The computer then sends radio-frequency (RF) signals to the RF modules corresponding to items on the order. Each RF module signaled corresponds to an item on the order. The signal causes a light on the RF module to be lit and the signal also includes a quantity desired for the order. A picking specialist then surveys the inventory sites, goes to those sites for which a light is lit, picks the desired quantity for the order, and signals that the particular item has been picked. While this method works, it is expensive to provide the modules for each location, and it is also expensive to maintain and power the modules. In addition, the picker must physically push a button or switch to indicate that the item has been picked.
Another system, disclosed in U.S. Pat. No. 6,650,225, offers an improvement over Danelski. The improved system includes a proximity detector near at least one of the modules or sites. The detector can report that there was activity or motion sensed in the vicinity of the module, thus inferring that the picking specialist was at least near the module. This may lead to false positives, i.e., an indication that the correct bin was picked when it was merely a nearby bin. If a “pitch and catch” LED system is used, a false negative may be generated, i.e., the correct bin was used, but insufficient light was reflected back to the sensor to generate a positive response. An improvement to the '225 patent is disclosed in U.S. Pat. No. 7,084,738. In the improvement, the module for each site is upgraded to include an image display. The display allows the picking specialist to more positively determine that the item in the bin or site corresponding to the module is the item desired. This will obviously be an expensive improvement.
Another system is disclosed in U.S. Pat. No. 6,775,588. The system disclosed in this patent uses a portable computer on a cart, the cart also having at least two bins for storing goods that are picked. As the operator moves the cart through the warehouse or inventory area, the wireless-equipped computer causes lights on display modules to illuminate. The display module, one per inventory item, illuminates its light in response to a signal from the computer, and also displays an indicia of the order number and quantity, so that the correct number of items can be placed into the correct bin on the cart. The computer can also indicate the desired location of goods to the operator. This system will be expensive, because of the need for modules at each warehouse location, and also because of the required computer and cart to carry out the order-picking process.
Each of the above systems has its strong points. The weak point for each system, in addition to any technical nuances, is its cost. Embodiments of the invention disclosed in this patent provide a picking system that is both cost-effective and efficient. These and other advantages of embodiments of the invention, as well as additional inventive features, will be apparent from the description provided herein.